Mortar is one of the oldest building materials. It consists of a mixture of one or more binders (lime, cement), water, and natural aggregates (quarry pit sand, shells, etc.) which after the binder has hardened and set acquires tremendous strength. Depending on the type of setting and hardening—which in turn depends on the type of cement used—mortars may be divided into hydraulic and non-hydraulic. Hydraulic mortars are those with the property of setting and hardening when they come into contact with water.
In the two-story building, which functioned as a water reservoir, Pozzolano-lime mortar (koursáni) was employed. Thanks to its hydraulic and insulation properties, it guaranteed that spaces would be waterproof. Its preparation involved lime, a clayey material, and ceramic powder (pulverized tiles), while one part of its natural aggregates was replaced with crushed pottery.
